Roller blinds, shutters and doors of various designs are well known. A simple roller blind, shutter or door comprises a roller mounted above a window, doorway or other opening and a sheet of flexible or slatted material wound onto the roller, which can be deployed into an unwound configuration to cover or close the opening. The opening may be provided with guide channels at either side in order to anchor the sides of the closed blind, shutter or door for increased stability or security. The opening and closing operation can be performed manually, for example using a side chain or cord, or can be motorised, for example by incorporating a motor drive mechanism within the roller.
Roller door systems are designed to allow people and equipment to move quickly through the doorway without obstruction e.g. by keeping the threshold as clear as possible, and without being inconvenient to operate e.g. by being too heavy, too slow or prone to jamming.
In situations where it is necessary to seal an opening against the ingress of smoke, contaminated air or particulates it is known to use a roller door system in which the top of the sheet material is secured to the top of the door frame and the roller itself moves relative to the opening. As the roller moves down over the opening the side edges of the sheet material can be progressively sealed to the door frame, for example by means of magnetic strips or hook and loop material. U.S. Pat. No. 5,383,510 (Allen) discloses an example of such a system.
It is an aim of the invention to provide an improved roller door system particularly, but not exclusively, suitable for use with tents and other lightweight, temporary or rapidly deployable structures, including, but not limited to: marquees, hangars, field hospitals and emergency shelters.